Gear transmission system



Oct J. L. C HRISTMANN GEAR TRANSMISSION SYSTEM Filed May 24, 1950INVENTORf JOHN LOUIS CHRISTMANN MW ATTOR v Oct. 28, 1952 J. L.CHRIISTMANN GEAR TRANSMISSION SYSTEM Filed May 24. 1950 gsasm's iam' zINVENTOR. JOHN LOUIS CHRISTMANN ATTORNEY Patented Oct. 28, 1952 "UNITEDSTATES PATENT OFFICE GEAR TRANSMISSION SYSTEM John LouisChristmann,.Pass,aic,,N. ,J.

' I -Applieation1May24, 195i), Serial No. 163,949

This invention relates to gear transmission systems, and has morparticular reference to systems of this type provided with '(1) lockingactions in one direction-of rotation, and'(2)' locking actions in bothdirections of rotation. Gear transmission systems of this type are useful 'in various mechanisms such as ratchet mechanisms, clutch mechanisms,brake mechanisms, variable speed mechanisms, and others;

The "new gear transmission system with looking action in one directionischaracterized by'a pair of meshing gears rotative on centers spaced toprovide sufiicient back-lash for the'gears tofreely rotate, and anarm-supporting one of said gears and fulcrumed to pivot ina-direction,whichwe shall characterize as forward, so as to reduce the centerdistance betweensaid gearsuntil-the backlash between'the teeth of themeshing gears is reduced to zero and said gears -pivot on their meshingteeth to a positively locked position against atorque applied to saidgears in a direction whichassists in moving said fulcrumed arm in saidforward direction. "It'is also proposed to provide means for moving-saidarm in said forward direction and-back-again so asto control the lockingand releasing-of said gear'transmission system. The lockingaction isstepless and independent of therelative angular relationship ofsaid-meshing'gears.

The new gear transmission systemwith locking action in "both directionsis" characterized by a rotative gear, a pair of gears meshing with saidfirst named gear and rotative'on centers spaced from 'the'center ofsaidfirst'named gear to provide sufficient backlash for all of said gear tofreely rotate, and arms supporting said pair of gears and fulcrumed topivot said pair of gears toward'and away from each other, reducing thecenter distance between said pair of gears and said first namedgear'upon moving said arms towards each other until the"backlash'between the meshing teeth is reduced to zero and said pair ofgears and said first named gear pivot on their meshing teeth toapositively locked position to torquesvin either direction. iIt is alsocontemplated to provide means for moving said arms towards and away fromeach other for locking and releasing said gears. The locking action isstepless.

The above features in gear transmission systems .as specified representsthe broad concept of this invention which may be used in a great manydifferent ways; some applications'of these ways will be given latroninthis specification; Before proceeding it may be advisableto pointout-that :9 claims. (01. 74-126) '2 the relative sizes of the gears arenot'important and they may beer the same or different sizes. It ispointed out however that the smaller the number of teeth on the gears ofthe gear pair supported-on the fulcrumed arms, the moreeffective is thelocking action. The manner of mounting the gears is also not importantsince-all gears may be mounted on fulcrumed or other arms, or they neednot be'so mounted, and the fulcrumed and. other-arms mayor may'not havecoaxial points of pivoting.

One way of utilizing the broad concepts of this invention would betoprovide a double gear attached coaxially to each of said pair of gearsand "to provide-a fourth gear preferably provided with an output shaft,said fourth gear meshing with said double gears and preferably disposedcoaxially of the fulcrumed arms of said pair of gears. In one form ofgear transmission system said shaft may comprise the output of thesystem. The input may be provided in numerous ways to give numerousdesired actions, such as a ratchet action to the system, a clutchaction, a brake action, and other types and kinds of actions.

One way of providing a suitable input makes use of a pair of eccentrics,links connectingsaid eccentrics with the two arms which control the lo kn la idre asin of the ar tr n mission system in both directions. ,ltisproposed to proyide means for .turningsaid eccentrics to control thelocking and releasingof thesystem. One way for turnin the eccentricswould be with the use of. a crankarm-provided witha hub coaxiallysupporting said eccentrics, a radial arm pivotally mounted onsaidshaft,and a link-connectingsaid radial arm with said crank arm, whereby uponmotion of the radial arm the eccentrics may be turned in one directionor the other forcontrolling .the locking and releasing of the system.

It :is pointed out that ithesystem referred to in the previous paragraphmay be operated like a ratchet by reciprocating the radial arm in orderthat-the gears lock during movement of the radial arm in one directionfor transmitting intermittent rotation to the output shaft in Onedirection, and releasing the gears so that the system idles withouttransmitting rotation in the other direction.

order that the invention maybe better understood three difierent geartransmission systems have been disclosed inthedrawings to illustrate oneembodiment-ofthe ratchet action, the clutch action, and the brakeactionpossible in accordancewiththis-invention.

Still further the invention proposes the con- For further comprehensionof the invention,

and of the object and advantages thereof, reference will be had to thefollowing description and accompanying drawings, and to the appendedclaims inwhich the various novel features of the invention are moreparticularly set forth.

In the accompanying drawings forming a material part of this disclosure-Fig. 1 is an end elevational view of a gear transmission system with aratchet action embodying this invention.

Fig. 2 is a fragmentary vertical sectional view taken on the line 2-2 ofFig. 1. Y

Fig. 3 is a fragmentary sectional view taken on the line 3-3 of Fig. 1.V

Fig. 4 is a fragmentary sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary enlargeddetailed view of one pair of meshinggears used in this transmission and illustrating the usual backlash sothat the gears are free to rotate.

Fig. 6 is a fragmentary view similar to Fig. 5 but showing the gearsmoved relative to each other so that the backlash has been decreased tozero to positively lock the gears.

Fig. 7 is a schematic view of three meshing gears embodied in thistransmission and indicating the manner in which the arms supporting twoof the gears are moved to move the gears into locking condition.

, Fig. 8 is a fragmentary sectional view similar to Fig. 2 butillustrating a gear transmission system with a brake action embodyingthis invention.

Fig. 9 is another fragmentary view similar to a portion of Fig. 2 butillustrating another gear transmission system with a clutch action inaccordance with this invention.

In Figs. 1-7 inclusive, a specific embodiment of the invention has beendisclosed for illustrative purposes. In thisembodiment the gear trans.-mission system is provided with a ratchet action. This embodimentincludes a stationary frame I8 provided with a pair of spaced bearingsII. A shaft I2 is rotatively'supported by the bearings II. A flangedbushing I3 is bushed on the shaft I2 for free rotation. A first arm I4is fulcrumed on the bushing I3 in order to be fulcrumed on the shaft I2.A gear I5 is rotatively mounted on said first arm I4. More particularly,the gear I5 is bushed upon a stud I6 which is mounted on said first armI4. A second arm IT and a third arm I8 are also fulcrumed on the bushingI3 in order to be fulcrumed on the. shaft I2. As illustrated in Fig. 1of the drawing the arms are in a position in which the arm I4 isvertical while the second and third arms I1 and I8, respectively, areinclined forward and rearwards, respectively.

A pair of gears 28 and 2| are rotatively mounted on said second andthird arms I! and I8, respectively, and mesh with said first named gearI5. This pair of gears 28 and 2| have their centers spaced from saidfirst named gear I5 to provide sufficient backlash for all of said gearsto rotate freely. This may be better understood by now examiningenlarged Fig.5 in which the gear 2| is illustrated meshing with the gearI5. Particular attention is called to the spaces 24 between the workingsurfaces of the teeth of the gears,

pitch distances.

4 which represents the sumcient backlash for the gears 2| and I5 torotate freely.

The second and third arms I! and I8 are capable of pivoting on saidbushing I3 towards and away from each other. For example, the top endsof these arms I! and I8 may pivot towards each other to cause thereductionof the center distances between the gears 28 and I5 and 2| andI5 until the backlash is zero and the gears 28 and 2| piVotLon the teethmeshing with gear I5 to positively lo'ck said "gears 20, 2| and I5 fromI turning. This may be better understood by examining Fig. 6 in whichthe gears 2| and I5 have been moved relative to each other into lockingpositions. In Fig. 5 the radius 25 of gear 2| is in a straight linewiththe radius 26 of gear I5 at the point of contact of the meshing teeth ontheir In Fig. 6 the gears have been illustrated moved so that the radius25 is now at an angle to the radius 26. This shifting of the gears 2|and I5 relative to each other until their center distances havedecreased to reduce the backlash to zero, causes the pivoting of thegears 2| and I5 ontheir meshing teeth as shown in Fig. 6. The lines 25and 26 illustrate the toggle effect which locks the gears 2| and I5.

Fig. '7 is a schematic illustration to simplify the relative positionsof the gears 20, 2| and I5 in their locking and in their free positions.In this schematic view thegears 28, 2| and I5 have been illustrated intheir free running positions by full line circles. The straight lines I!and I8 represent the arms I1 and I8 which support the gears 28 and 2|,respectively. The pivot point 21 of the arms I! and I8 represent theaxis of the shaft I2. When the arms I] and I8 are moved towards eachother, as indicated by the arrows 28, the gears 2I| and 2| will be movedtowards each other to the positions indicated by the dotted lines 20'and 2|. In these latter positions the radii of the gears 28 and I5, and2| and I5 will be at angular positions, as clearly illustrated by thedotted lines 25' and 26. The full line positions of the radii of thegears 20, 2| and I5 are indicated by the reference numerals 26 and 26,respectively. It is pointed out that the gears 20, .2I and I5 would alsolockif the arms I! and I8 were moved apart instead of together, providedthe fulcrums of the arms I! and |6 were disposed above the center ofgear I5 that the gears 20 and 2| are moved towards gear I5.

A somewhat clearer understandin'g of the locking action may becomprehended by considering, for example, just gears I5 and 2| and thearm I8, reference being had to Fig. '7. At the time of the lockingmovement two distinct and simultaneous actions take place whichcontributes to the locking effect. One action is a wedging actionbetween gears 2| and I5 due to the arm I8 pivoting on the point 21 andforcing gear 2| towards gear I5 when the' arm I8. moves in the direction28. The second action is the pivoting action of the gears 2| and I5around their meshing teeth forming a toggle effect alone, the radiilines 25'. and26'. This toggle cannot be straightened out by a torque in'a clockwise direction by a gear" I5"sir'1c'e the arm I8 cannot stretchand therefore the wedging action between gears 2I' and I5 is increased.by the torque. An anti-clockwisetorque of gear I5 would decrease thewedging action and cause straightening of said toggle sozthen we do notget a positivelocking action in thisi direction. j V

scribediin itscbroadest concept.. In other words, we.- can now ,1produce -a. ;:gear transmission :system whichxmay :be .locked.;in tonevdirection of rotation, .and a "secondrgear transmission system which'may :be locked in both directions of rotation. It is. also important:to;no.te the "locking :positions .will work irrespective ,of therelative :size .of the gears, and irrespectiveof..,the manner in whichthe-gears are mounted, limited only by the requirement that they becapable of .beingmoved into and out of locking positions. There are anynumberof waysgin which this broad concept. of the .invention may, beutilized, reference being "made to .;.using various inputs and outputs.tothe locking arrangement.

The particular .input :and nutput ,of thatform of. theinvention.sho.wn.in,.Figs. 1-,.7 inclusive will now Joe-consideredzinrdetail. ,Adouble gear 3|] is. coaxially attached to ea.ch of said pair of gears 20andll. This -,isaccomplished .by-providing each of the gears 28 and 2]with ,hubs 3| andmounting the double :gears 30.,upon these hubs 3|.Thehubs of thegears 30 and3lyare secured together with pins32. Afourth.gear 33 is mounted, on the shaft .12 and mesheswith said double gears30. In the particular design shown, this fourth gear 33 is secured tothe shaft l2 with a key 34. The arms 14, I1 and 18 are reinforced withcomplementary arms 1 and spacer. This construction includes a-bushing 35bushed on the shaft l2. Anarm 36-is pivotally mounted on the bushing 35and is complementary tothefirst arm and connected to the first arm byspacers 31. ,An arm 39 is fulcrumed on the bushing ;35 and iscomplementary. to the third arm I8 and is rigidly connected therewith byspacers 40. Another arm 4| is complementary to the second arm I! and isrigidly :connected therewith by spacers 38.

A crank arm 45 is pivotally mounted on said first arm 14 ,bypivotallyengaging. on an'extension 42 of. .the top spacer 31. This crank arm 45has a horizontal section 46 :and a downwardly extending vertical section41. The section 4'! is provided with a slot 48 which engages, overanrextension 49 of the stud I6 so asto limit the pivoting of the crankarm 45. The crank arm :45 is provided witha ,hub 49': upon whichapair ofeccentrics 50 and 51 are keyed. These eccentrics are substantially 180from each other. upon the eccentrics 50 and respectively, and pivotallyconnect with the arms I1 and 18,1 re,- spectively. The top spacers 38and 40 of the arms ll and-l8 are provided-with-extensions 55 upon whichthe links 53 and 54 are pivotally mounted.

;-A radial arm 58 is bushed on the shaft l2 and Links-53 and 54arepivotally mounted is provided with a hub ,59 which extends throughone of the bearings ll of'the'stationary frame It). Alink 60 ispivotallymounted upon the outer endof the section .46 of the .crank arm45 and pivotally connects with the outer end of the radial arm 58. Aradial arm 62 is keyed upon the outer end of the hub 59 and connectswith an arm 63 which may be reciprocated by some mechanism, not shown. Acollar 64 is pinned to The rod 63 may be reciprocated upwards anddownwards any desired amount to transmit anintermitt'entaforward{rotation to .the loutpunshaft I2. For example,when the rod 63 ;moves:aul wards the radial arm :62 will movecorrespondingly and movethe radialarm58 which through thelinks .60pivots .the' crank arm i45yclockwise against the stop extension 49.Since .theeccentrics' 5fl and.5l aremounted on'the hub ofwthe crank arm45 they-will correspondingly ;:turn and move the links 53 and apartas-limited by the :slot 48 strikingithe extension49 of the stud I6. Whenthelinks .53 and 54 are moved apart they'corres'pondingly pivot the armsl1 and IB'apart into positions in which thegears .20and 2| are free torotate with the gear [5. Because the gears 20, '2! and 15 are free torotate the rod 63 may bemoved upwards any amountcorrespondingly pivotingthe frames formed-by'the arms I4',"36 and IT, 4| and 1'8, 3.9,and thedouble gears--30 will merely idle around the gear-33. When the rod 63moves downward the gears will lock before' the slotted extension ofcrank 45 touches the pin 49. The eccentrics 50 and5| are adjusted sothat the pin 49 will allow just the correctamount of backlash for thegears when they are free, the locking actionforms its own limit stop onthe locking part of the stroke. Iii-this second position the eccentrics50 and -5| move the links 53 and 54 together causing the backlashbetween the gears to decrease to zero 'and'the gears to pivot on theirmeshing "teeth.

to a positively locked condition in either direction. I SincethegearsZil and 2| are now locked; the doublegears 30 will rotate thegear 33 a dis tance correspondin -withthe downward motion of the rod '63which communicated to said frames. Consequentlythe shaft I12 will bedriven forwards intermittently as the rod 63 reciprocates. Thiscorresponds to a ratchet action.

In Fig. 8a modified form of gear transmission system hasbeen disclosedwhich includes a brake action. The brake action may be obtained byanchoring one'of the arms which are fulcrumed on the shaft I2, andforillustrative purposes arm l4 has been anchored. Abracket 65 has "beenmounted upon the frame It about the spacer 31- so as to anchor the arm[4 in a stationary position. In other respects thisform of the inventionis identical to the previous form and like parts havebeen indicated bylike reference numerals. .This' modified device may now'act as 'a brakesystem.=zWhen.the radial arm 62 is in-a raised position-so that thegears are free to rotate, the gear l5 may be driven ineitherdirection-by mechanism, =notillustrated on the drawing, throughthegear- 33 and the shaft l2. The

brake is applied by merely moving the radial arm 62 downwards so thatthe crank arm 45 is pivoted-to its second position in which the gearslock, as already described. v.This'locking of the gears against rotationin either direction applies thev brake. to .the system. when driven ineither direction. It is obviouswthat if .the gear transmission-systemwere modified to eliminate "one of the gears 20 or 2| then the brakewill operate when the gear system is driven in one direction only. Whenthe two gears 20 and 2| are used then the brake will operate with thegear transmission system driven in either direction.

In Fig. 9 another modified form of the invention has been disclosedwhich has been modified to act as a clutch. In this form of theinvention a gear 66 is substituted for the radial arm 62. In otherrespects this form of the invention is identical to the previous formsand like parts are identified by like reference numerals.

The operation of this form of the invention is as follows:

When the gear 66 is driven in one direction a torque will be transmittedto the radial arm 58 through the link 60, to the crank arm 45 so as topivot the crank arm 45 to cause the links 53 and 54 to separate and movethe systeminto a position in which the gears are unlocked: Now theclutch is open because no rotations will be transmitted from the gear 66to the gear 33. When the gear 66 is driven in the other direction theradial arm 58 will be moved downwards and indirectly pivot the crank arm45 so as to draw the links 53 and 54 together, moving the gears of thesystem into locking condition. When the gears are locked rotations willbe transmitted from gear 66 to the gear 33 which now corresponds withthe closed condition of the clutch.

While I have illustrated and described the preferred embodiments of myinvention, it is to be understood that I do not limit myself to theprecise constructions herein disclosed andthe right is reserved to allchanges and modifications coming within the scope of the invention asdefined in the appended claims.

Having thus described my invention, what Iv claim as new and desire tosecure by United States Letters Patent is:

1. In a gear transmission system, a stationary frame, a shaft rotativelymounted on said frame,

a first arm fulcrumed on said shaft, a gear rotative on said first arm,a second and third arm fulcrumed on said shaft, a pair of gears rotativeon said second and third arms and meshing with said first named gear andhaving their centers spaced from the center of said first named gear Ito provide sufiicient backlash for all of said gears to freely rotate,and means for pivoting said second and third arms toward each other tomove said pair of gears towards each other and lock them togetheragainst rotation.

2. .In a gear transmission system, a stationary frame, a shaftrotatively mounted on said frame, a first arm fulcrumed on said shaft,2. gear rotativeon said first arm, a second and third arm I tiveon saidfirst arm, a second and third arm fulcrumedon said shaft, a pair ofgears rotative on said second and third arms and meshing with said firstnamed gear and having their centers spaced from the center of said firstnamed gear to provide sufiicient backlash for all of said gears tofreely rotate, and said second and third arms being capable of pivotingtowards each other to move said pair of gears towards each other, adouble gear attached to each of said pair of gears, a fourth gearmounted on said shaft and meshing with said double gears, a crank armpivotally mounted on said first arm, a pair of eccentrics substantially180 from each other and coaxially mounted on said crank arm, linksconnecting said eccentrics with said second and third arms, a radial armpivotally mounted on said shaft, and a link connecting said radial armwith said crank arm, whereby said radial arm may be moved in onedirection to lock said gears and in the other to free said gears.

4. A gear transmission system as defined in claim 3, in which said crankarm is provided with a slot, and a stop is mounted on said first arm andengages said slot for limiting the motion of said eccentrics.

5. A gear transmission system as defined in claim 3, in which a doubleradial arm is connected With said radial arm for the operation of thelatter arm.

6. A gear transmission system as defined in claim 3, in which a gear isrotatively mounted on said shaft and is fixedly connected with saidradial arm by which said fourth gear may be driven in either directionto positively drive the shaft in that direction.

7. A gear transmission system as defined in claim 3, in which means isprovided for holdin said first arm in a stationary position.

8. A gear transmission system as defined in claim 3, in which means isprovided for holding one of said first, second and third arms in astationary position.

9. A gear transmission system as defined in claim 1, in which armscomplementary to said first, second and third arms are fulcrumed on saidshaft and rigidly connected respectively with said first, second, andthird arms with spacers.

' JOHN LOUIS CI-IRLIS'IMANN.

REFERENCES CITED The following references are of record in the file ofthis patent:

mounted on said shaft and meshing with said double gears, whereby whensaid pair of gears" are locked said arms may be turned on said shaft tocause said pair of locked gears to turn said

